Hi @Robert D . I had the same issue and I figured out the font I was using for my community was not a free licensed font from Google Font. It seems that you have customized the font in your community. The font you are using seems to be a customized font which is available for your computer. But, it is not a popular and free font from google fonts, so not everyone (every device) has access to it.
Tribe supports the Google Fonts, which is a library of 960 free licensed fonts, an interactive web directory for browsing the library, and APIs for conveniently using the fonts via CSS and Android.
I would recommend to use a free and know font from google font in your community.